Aluminum, threaded body, double adjustable monotube QA1 shocks. Hyperco high silicone wire coil spring. Offset Trailing Arms with Coilover Bracket. Upper shock mount reinforcement kit. There are a lot of important benefits as spring and shock tuning allows you to set up the suspension to suit your car much better than with any other system. The spring coiling the shock means that the shock and spring operate at the same rate regarding the wheel rate. Also, placing the coilover closer to the axis center line will have a spring and shock rate closer to the wheel rate. This enables you to respond quicker and it's more sensitive to smaller movements. The shock is more rigidly mounted for maximum durability of the package. Then there's the benefit of the shocks being rebuildable, re-valve-able, and generally much higher quality than OE shocks. The coilovers give true independence and allow you to fine tune the rear suspension. NOTE: 1963-64 Cars need to convert to disc brakes. Will not work with drum brakes.